Table of Contents

Moduli spaces of curves with effective $r$-spin structures by A. Polishchuk A construction of Witten's top Chern class in $K$-theory by A. Chiodo Witten's conjecture and the Virasoro conjecture for genus up to two by Y.-P. Lee Idempotents on the big phase space by X. Liu Singularities with symmetries, orbifold Frobenius algebras and mirror symmetry by R. M. Kaufmann The cohomology ring of crepant resolutions of orbifolds by Y. Ruan Differential characters on orbifolds and string connections I: Global quotients by E. Lupercio and B. Uribe HKR characters and higher twisted sectors by J. Morava Combinatorics of binomial decompositions of the simplest Hodge integrals by S. V. Shadrin The orbifold cohomology of the moduli of genus-two curves by J. Spencer.